A formal test of the theory of universal common ancestry

  title={A formal test of the theory of universal common ancestry},
  author={Douglas L. Theobald},
Universal common ancestry (UCA) is a central pillar of modern evolutionary theory. As first suggested by Darwin, the theory of UCA posits that all extant terrestrial organisms share a common genetic heritage, each being the genealogical descendant of a single species from the distant past. The classic evidence for UCA, although massive, is largely restricted to ‘local’ common ancestry—for example, of specific phyla rather than the entirety of life—and has yet to fully integrate the recent… 

Origins of life: Common ancestry put to the test

Douglas Theobald has framed the UCA view as a formal hypothesis and put it to the test using Bayesian statistical analysis of the sequences of universally conserved proteins and contrasting the results with alternative models where genetic similarity is not assumed to reflect phylogenetic relatedness.

On universal common ancestry, sequence similarity, and phylogenetic structure: the sins of P-values and the virtues of Bayesian evidence

A formal, quantitative test of UCA in which model selection criteria overwhelmingly choose common ancestry over independent ancestry, based on a dataset of universally conserved proteins, demonstrates that real universally Conserved proteins are homologous, a conclusion based primarily on the specific nested patterns of correlations induced in genetically related protein sequences.

Was the universal common ancestry proved?

It is thought that the test of Theobald is not sufficient enough to reject the alternative hypothesis of the separate origins of life, despite the Akaike information criterion (AIC) of model selection giving a clear distinction between the competing hypotheses.

The common ancestry of life

A computational experiment on a concatenated alignment of universally conserved proteins shows that the purported demonstration of the universal common ancestry is a trivial consequence of significant sequence similarity between the analyzed proteins.

Statistical evidence for common ancestry: New tests of universal ancestry

The novel statistical methods presented here provide formal means to test separate ancestry versus common ancestry from aligned DNA sequence data while accounting for functional constraints that limit nucleotide base usage on a site-by-site basis.

Universal common ancestry, LUCA, and the Tree of Life: three distinct hypotheses about the evolution of life

It is argued that the existence of a Tree of Life entails a last universal common ancestor, which would entail universal common ancestry, but neither of the converse entailments hold.

Statistical evidence for common ancestry: Application to primates

A diversity of statistical methods using data from the primates are explored, including one that tests for phylogenetic autocorrelation while correcting for variation due to confounding ecological traits and a method for examining whether fossil taxa have fewer derived differences than living taxa.

Infinitely long branches and an informal test of common ancestry

It is concluded that the UCA test as originally proposed should not be trusted unless convergence has already been ruled out a priori, and a class of frequentist tests that perform better than the purportedly formal U CA test are presented.

Some Problems in Proving the Existence of the Universal Common Ancestor of Life on Earth

It is shown that the alignment gives a strong bias for the common ancestor hypothesis, and an example that Theobald's method supports a common ancestor hypotheses for two apparently unrelated families of protein-encoding sequences is provided.

Reconstructing the Last Common Ancestor: Epistemological and Empirical Challenges

It is argued that LGT poses insurmountable challenges for detailed and rich in details reconstructions and proposed a middle-ground position with the reconstruction of a slim LCA based on traits under strong pressures of Negative Natural Selection, and for the need of consilience with evidence from organismal biology and geochemistry.



Testing the hypothesis of common ancestry.

This work reviews and critically examines some arguments that have been proposed in support of the hypothesis that all life on earth traces back to a single common ancestor, and describes some theoretical results that suggest the hypothesis may be intrinsically difficult to test.

Evaluating hypotheses for the origin of eukaryotes.

  • A. PooleD. Penny
  • Biology
    BioEssays : news and reviews in molecular, cellular and developmental biology
  • 2007
The conclusion is that the eukaryote lineage must have diverged from an ancestor of archaea well prior to the origin of the mitochondrion, and the absence of ancestrally amitochondriate eUKaryotes (archezoa) among extant eucaryotes is neither evidence for an archaeal host for the ancestor of mitochondria, nor evidence against a eukARYotic host.

On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for Life

Charles Darwin's seminal formulation of the theory of evolution, "On the Origin of Species" continues to be as controversial today as when it was first published. This "Penguin Classics" edition

The practice of classification and the theory of evolution, and what the demise of Charles Darwin's tree of life hypothesis means for both of them

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  • Biology
    Philosophical Transactions of the Royal Society B: Biological Sciences
  • 2009
It is argued that for Darwin the tree of life was a hypothesis, which lateral gene transfer in prokaryotes now shows to be false, and a more general and relaxed evolutionary theory is proposed.

Testing fundamental evolutionary hypotheses.

The Origin of Species by Means of Natural Selection, Or, The Preservation of Favoured Races in the Struggle for Life

The Origin of Species is a rigorously documented but highly readable account of the scientific theory that now lies at the root of the authors' present attitude to the universe.

The ring of life provides evidence for a genome fusion origin of eukaryotes

The general outline of the tree of life is determined using complete genome data from representative prokaryotes and eukaryote and a new genome analysis method that makes it possible to reconstruct ancient genome fusions and phylogenetic trees.

Evolution: The Modern Synthesis

This definitive edition brings one of the most important and successful scientific books of the twentieth century back into print and includes the entire text of the 1942 edition, Huxley's introduction to the 1963 second edition (which demonstrates his continuing command of the field), and the introduction tothe 1974 third edition, written by nine experts from different areas of evolutionary biology.

Universal trees based on large combined protein sequence data sets

Combined protein universal trees are highly congruent with SSU rRNA trees in their strong support for the separate monophyly of domains as well as the early evolution of thermophilic Bacteria.

On the Occurrence of Horizontal Gene Transfer Among an Arbitrarily Chosen Group of 26 Genes

  • M. Syvanen
  • Biology
    Journal of Molecular Evolution
  • 2001
It is shown, using the distance matrix rate test, that the rate of evolution of these two proteins is comparable to a control gene when rates are determined by comparing closely related species, which implies that the genes under comparison experience comparable functional constraint.